The 1.76.1 stylesheets added the capability of
making cleaner HTML and generating one or two CSS files when chunking.
That avoids the need for copying the CSS file into place after building the
HTML. Because HTML5 pretty much needs the clean HTML and CSS, I turned on
that feature for the xhtml5 stylesheets. See these three params for a
description of how to make cleaner HTML with CSS for styling: